The invention relates to compositions, methods, and apparatuses for improving the inhibition of scale deposition. More specifically, the invention relates to a method of inhibiting scale deposition in process solution distribution systems consisting of piping, spray nozzles, and emitter tubes such as those used in heap leach mining operations.
In heap leach mining operations, a heap of valuable mineral containing ore is placed on a containment liner system (also known as a heap leach pad) and continuously sprayed or irrigated with a process solution, commonly referred to as barren solution, to wet the entire ore heap. The barren solution selectively extracts or leaches the valuable mineral(s) in the ore as the solution infiltrates through the ore heap. The solution collected after leaching which contains the targeted, valuable mineral(s) is known as pregnant solution. The pregnant solution is collected at the bottom of the ore heap and is transported to processing equipment, where the targeted valuable mineral(s) are selectively separated or recovered and barren solution is recycled to the heap. If lower than desired targeted mineral concentration is achieved in the pregnant solution, this solution, often referred to a lean pregnant solution, can be recycled to the heap for further leaching.
One problem commonly faced in heap leach mining operations is the precipitation and accumulation of mineral scale deposits in process solution distribution systems. Such scale impairs or clogs the flow of the process solution which can result in such problems as incorrect or inadequate dosage of barren or lean pregnant solution added to the heap, damage to solution distribution systems, loss of effectiveness of the solution, and increased energy needed to pump the solution through the solution distribution system. Currently such problems are addressed by feeding scale control reagents to protect the solution distribution system against mineral scale related plugging or damage, and to assure adequate flow rates.
The quantity or dosage of scale control reagent required for effective deposit control is dependent upon soluble mineral concentrations in the process solution in combination with physical stresses that impact saturation levels. Saturation levels are often highly variable impacted by variations in ore subjected to leach, make-up water volume and composition, process additive rates, and physical stress changes. Dosage rates of scale control reagent are however commonly held constant, often resulting in overdose (reagent waste) or under dose (inadequate control of scale) as conditions vary.
There thus exists an ongoing need to develop alternative and more efficient methods of controlling scale control reagent dosages applied to process solution distribution systems including those used in heap leach mining operations.
The art described in this section is not intended to constitute an admission that any patent, publication or other information referred to herein is “prior art” with respect to this invention, unless specifically designated as such. In addition, this section should not be construed to mean that a search has been made or that no other pertinent information as defined in 37 CFR §1.56(a) exists.